Co-Ordinated Sensorless Control System

ABSTRACT

A method and system for co-ordinating control of a plurality of sensorless devices. Each device includes a communication subsystem and configured to self-detect one or more device properties, the device properties resulting in output having one or more output properties. The method includes: detecting inputs including the one or more device properties of each device, correlating, for each device, the detected one or more device properties to the one or more output properties, and co-ordinating control of each of the devices to operate at least one of their respective device properties to co-ordinate one or more output properties for the combined output to achieve a setpoint. In some example embodiments, the setpoint can be fixed, calculated or externally determined.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application under 35 U.S.C. § 111(a)of U.S. patent application Ser. No. 15/785,055 filed Oct. 16, 2017 andentitled CO-ORDINATED SENSORLESS CONTROL SYSTEM, which is a continuationapplication under 35 U.S.C. § 111(a) of U.S. patent application Ser. No.14/441,037 entitled CO-ORDINATED SENSORLESS CONTROL SYSTEM, which issuedas U.S. Pat. No. 9,829,868 on Nov. 28, 2017, which is a National StageApplication entered May 6, 2015 under 35 USC § 371 of PCT/CA2013/050867filed Nov. 13, 2013 entitled CO-ORDINATED SENSORLESS CONTROL SYSTEM,which claims the benefit of priority to U.S. Provisional PatentApplication No. 61/736,051 filed Dec. 12, 2012 entitled “CO-ORDINATEDSENSORLESS CONTROL SYSTEM”, and to U.S. Provisional Patent ApplicationNo. 61/753,549 filed Jan. 17, 2013 entitled “SELF LEARNING CONTROLSYSTEM AND METHOD FOR OPTIMIZING A CONSUMABLE INPUT VARIABLE”, all ofwhich are herein incorporated by reference in their entirety into theDetailed Description of Example Embodiments, herein below.

TECHNICAL FIELD

Some example embodiments relate to control systems, and some exampleembodiments relate specifically to flow control systems.

BACKGROUND

In pumping systems where the flow demand changes over time there areseveral conventional procedures to adapt the operation of the pump(s) tosatisfy such demand without exceeding the pressure rating of the system,burning seals or creating vibration, and they may also attempt tooptimize the energy use.

Traditional systems have used one or several constant speed pumps andattempted to maintain the discharge pressure constant, when the flowdemand changed, by changing the number of running pumps and/or byoperating pressure reducing, bypass and discharge valves.

One popular system in use today has several pumps; each equipped with anelectronic variable speed drive, and operates them to control one ormore pressure(s) remotely in the system, measured by remote sensors(usually installed at the furthest location served or ⅔ down the line).At the remote sensor location(s) a minimum pressure has to bemaintained, so the deviation of the measured pressure(s) with respect tothe target(s) is calculated. The speed of the running pumps is thenadjusted (up or down) to the lowest that maintains all the measuredpressures at or above their targets. When the speed of the running pumpsexceeds a certain value (usually 95% of the maximum speed), another pumpis started. When the speed falls below a certain value (50% or higher,and sometimes dependent on the number of pumps running), a pump isstopped. This sequencing method is designed to minimize the number ofpumps used to provide the required amount of flow.

An alternative to this type of system measures the flow and pressure atthe pump(s) and estimates the remote pressure by calculating thepressure drop in the pipes in between. The pump(s) are then controlledas per the procedure described above, but using the estimated remotepressure instead of direct measurements. This alternative saves the costof the remote sensor(s), plus their wiring and installation, butrequires a local pressure sensor and flow meter.

One type of pump device estimates the local flow and/or pressure fromthe electrical variables provided by the electronic variable speeddrive. This technology is typically referred to in the art as“sensorless pumps” or “observable pumps”. Example implementations usinga single pump are described in WO 2005/064167, U.S. Pat. Nos. 7,945,411,6,592,340 and DE19618462. The single device can then be controlled, butusing the estimated local pressure and flow to then infer the remotepressure, instead of direct fluid measurements. This method saves thecost of sensors and their wiring and installation, however, thesereferences may be limited to the use of a single pump.

Another such application, where multiple pumps are coordinated to eachprimarily satisfy a specific corresponding load for each pump, isdescribed in U.S. 2010/0300540.

Additional difficulties with existing systems may be appreciated in viewof the description below.

SUMMARY

In accordance with some aspects, there is provided a co-ordinatedsensorless flow control system for circulating devices such as pumps,boosters and fans, centrifugal machines, and related systems. The systemincludes a plurality of sensorless pumps which operate in a co-ordinatedmanner to achieve a setpoint. For example, the sensorless pumps may bein a parallel configuration, to serve a desired system load. Thepressure setpoint can be common to all of the circulating devices,typically determinable for a specific location which is sourced by allof the circulating devices.

In one aspect, there is provided a control system for sourcing a load,including: a plurality sensorless circulating devices each including arespective circulating operable element arranged to source the load,each device configured to self-detect power and speed of the respectivedevice; and one or more controllers configured to: correlate, for eachdevice, the detected power and speed to one or more output propertiesincluding pressure and flow, and co-ordinate control of each of thedevices to operate at least the respective circulating operable elementto co-ordinate one or more output properties for the combined output toachieve a pressure setpoint at the load.

In one aspect, there is provided a control system, including: two ormore devices, each device having a communication subsystem andconfigured to self-detect one or more device properties, the deviceproperties resulting in output having one or more output properties; andone or more controllers configured to: detect inputs including the oneor more device properties of each device, correlate, for each device,the detected one or more device properties to the one or more outputproperties, and co-ordinate control of each of the devices to operate atleast one of their respective device properties to co-ordinate one ormore output properties for the combined output to achieve a setpoint.

In some example embodiments, the setpoint can be fixed, calculated orexternally determined.

In another aspect, there is provided a method for co-ordinating controlof two or more devices, each device having a communication subsystem andconfigured to self-detect one or more device properties, the deviceproperties resulting in output having one or more output properties, themethod including: detecting inputs including the one or more deviceproperties of each device; correlating, for each device, the detectedone or more device properties to the one or more output properties; andco-ordinating control of each of the devices to operate at least one oftheir respective device properties to co-ordinate one or more outputproperties for the combined output to achieve a setpoint.

In another aspect, there is provided a non-transitory computer readablemedium having instructions stored thereon executable by one or moreprocessors for co-ordinating control of two or more devices, each devicehaving a communication subsystem and configured to self-detect one ormore device properties, the device properties resulting in output havingone or more output properties, the instructions including: instructionsfor detecting inputs including the one or more device properties of eachdevice; instructions for correlating, for each device, the detected oneor more device properties to the one or more output properties; andinstructions for co-ordinating control of each of the devices to operateat least one of their respective device properties to co-ordinate one ormore output properties for the combined output to achieve a setpoint.

In another aspect, there is provided a device for co-ordinating with oneor more other devices, each of the one or more other devices configuredto self-detect one or more device properties, the device propertiesresulting in output having one or more output properties. The deviceincludes: a detector configured to self-detect one or more deviceproperties; the device properties resulting in output having one or moreoutput properties; memory for storing a correlation between the one ormore device properties and the one or more output properties; acontroller configured to correlate, for the device, the detected one ormore device properties to the one or more output properties; acommunication subsystem for receiving the detected one or more deviceproperties or correlated one or more output properties of the one ormore other devices, and for sending instructions to the one or moreother devices to co-ordinate control of each of the devices to operateat least one of their respective device properties to co-ordinated oneor more output properties of the devices for the combined output toachieve a setpoint; and an output subsystem for controlling the at leastone of device properties of the device to achieve the setpoint.

In another aspect, there is provided a device for co-ordinating with oneor more other devices, each of the one or more other devices configuredto self-detect one or more device properties, the device propertiesresulting in output having one or more output properties. The deviceincludes: a controller; a detector configured to self-detect one or moredevice properties, the device properties resulting in output having oneor more output properties; memory for storing a correlation between theone or more device properties and the one or more output properties; acommunication subsystem for sending the detected one or more deviceproperties or the correlated one or more output properties of the deviceand for receiving instructions to operate at least one of the deviceproperties of the device to co-ordinate one or more output properties ofthe devices for the combined output to achieve a setpoint; and an outputsubsystem for controlling the at least one of the device properties ofthe device in response to said instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, withreference to the attached Figures, wherein:

FIG. 1 illustrates an example block diagram of a circulating systemhaving intelligent variable speed control pumps, to which exampleembodiments may be applied;

FIG. 2 illustrates an example range of operation of a variable speedcontrol pump;

FIG. 3 shows a diagram illustrating internal sensing control of avariable speed control pump;

FIG. 4 illustrates an example load profile for a system such as abuilding;

FIG. 5 illustrates an example detailed block diagram of a controldevice, in accordance with an example embodiment;

FIG. 6 illustrates a control system for co-ordinating control ofdevices, in accordance with an example embodiment;

FIG. 7 illustrates another control system for co-ordinating control ofdevices, in accordance with another example embodiment; and

FIG. 8 illustrates a flow diagram of an example method for co-ordinatingcontrol of devices, in accordance with an example embodiment.

Like reference numerals may be used throughout the Figures to denotesimilar elements and features.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In some example embodiments, there is provided a control system for anoperable system such as a flow control system or temperature controlsystem. Example embodiments relate to “processes” in the industrialsense, meaning a process that outputs product(s) (e.g. hot water, air)using inputs (e.g. cold water, fuel, air, etc.).

It would be advantageous to provide a system which controls operation ofa plurality of sensorless pumps in a co-ordinated manner.

At least some example embodiments generally provide a co-ordinatedsensorless automated control system for circulating devices such aspumps, boosters and fans, centrifugal machines, and related systems. Forexample, in some embodiments the system may be configured to operatewithout external sensors to collectively control output properties to aload.

In one example embodiment, there is provided a control system forsourcing a load, including: a plurality of sensorless circulatingdevices each including a respective circulating operable elementarranged to source the load, each device configured to self-detect powerand speed of the respective device; and one or more controllersconfigured to: correlate, for each device, the detected power and speedto one or more output properties including pressure and flow, andco-ordinate control of each of the devices to operate at least therespective circulating operable element to co-ordinate one or moreoutput properties for the combined output to achieve a pressure setpointat the load.

Reference is first made to FIG. 1 which shows in block diagram form acirculating system 100 having intelligent variable speed circulatingdevices such as control pumps 102 a, 102 b (each or individuallyreferred to as 102), to which example embodiments may be applied. Thecirculating system 100 may relate to a building 104 (as shown), a campus(multiple buildings), vehicle, or other suitable infrastructure or load.Each control pump 102 may include one or more respective pump devices106 a, 106 b (each or individually referred to as 106) and a controldevice 108 a, 108 b (each or individually referred to as 108) forcontrolling operation of each pump device 106. The particularcirculating medium may vary depending on the particular application, andmay for example include glycol, water, air, and the like.

As illustrated in FIG. 1, the circulating system 100 may include one ormore loads 110 a, 110 b, 110 c, 110 d, wherein each load may be avarying usage requirement based on HVAC, plumbing, etc. Each 2-way valve112 a, 112 b, 112 c, 112 d may be used to manage the flow rate to eachrespective load 110 a, 110 b, 110 c, 110 d. As the differential pressureacross the load decreases, the control device 108 responds to thischange by increasing the pump speed of the pump device 106 to maintainor achieve the pressure setpoint. If the differential pressure acrossthe load increases, the control device 108 responds to this change bydecreasing the pump speed of the pump device 106 to maintain or achievethe pressure setpoint. In some example embodiments, the control valves112 a, 112 b, 112 c, 112 d can include faucets or taps for controllingflow to plumbing systems. In some example embodiments, the pressuresetpoint can be fixed, continually or periodically calculated,externally determined, or otherwise specified.

The control device 108 for each control pump 102 may include an internaldetector or sensor, typically referred to in the art as a “sensorless”control pump because an external sensor is not required. The internaldetector may be configured to self-detect, for example, deviceproperties such as the power and speed of the pump device 106. Otherinput variables may be detected. The pump speed of the pump device 106may be varied to achieve a pressure and flow setpoint of the pump device106 in dependence of the internal detector. A program map may be used bythe control device 108 to map a detected power and speed to resultantoutput properties, such as head output and flow output (H, F).

Referring still to FIG. 1, the output properties of each control device102 are controlled to, for example, achieve a pressure setpoint at thecombined output properties 114, shown at a load point of the building104. The output properties 114 represent the aggregate or total of theindividual output properties of all of the control pumps 102 at theload, in this case, flow and pressure. In typical conventional systems,an external sensor (not shown) would be placed at the location of theoutput properties 114 and associated controls (not shown) would be usedto control or vary the pump speed of the pump device 106 to achieve apressure setpoint in dependence of the detected flow by the externalsensor. In contrast, in example embodiments the output properties 114are instead inferred or correlated from the self-detected deviceproperties, such as the power and speed of the pump devices 106, and/orother input variables. As shown, the output properties 114 are locatedat the most extreme load position at the height of the building 104 (orend of the line), and in other example embodiments may be located inother positions such as the middle of the building 104, ⅔ from the topof the building 104 or down the line, or at the farthest building of acampus.

One or more controllers 116 (e.g. processors) may be used to co-ordinatethe output flow of the control pumps 102. As shown, the control pumps102 may be arranged in parallel with respect to the shared loads 110 a,110 b, 110 c, 110 d. For example, the individual output properties ofeach of the control pumps 102 can be inferred and controlled by thecontroller 116 so as to achieve the aggregate output properties 114.This feature is described in greater detail below.

In some examples, the circulating system 100 may be a chilledcirculating system (“chiller plant”). The chiller plant may include aninterface 118 in thermal communication with a secondary circulatingsystem for the building 104. The control valves 112 a, 112 b, 112 c, 112d manage the flow rate to the cooling coils (e.g., load 110 a, 110 b,110 c, 110 d). Each 2-way valve 112 a, 112 b, 112 c, 112 d may be usedto manage the flow rate to each respective load 110 a, 110 b, 110 c, 110d. As a valve 112 a, 112 b, 112 c, 112 d opens, the differentialpressure across the valve decreases. The control device 108 responds tothis change by increasing the pump speed of the pump device 106 toachieve a specified output setpoint. If a control valve 112 a, 112 b,112 c, 112 d closes, the differential pressure across the valveincreases, and the control devices 108 respond to this change bydecreasing the pump speed of the pump device 106 to achieve a specifiedoutput setpoint.

In some other examples, the circulating system 100 may be a heatingcirculating system (“heating plant”). The heater plant may include aninterface 118 in thermal communication with a secondary circulatingsystem for the building 104. In such examples, the control valves 112 a,112 b, 112 c, 112 d manage the flow rate to heating elements (e.g., load110 a, 110 b, 110 c, 110 d). The control devices 108 respond to changesin the heating elements by increasing or decreasing the pump speed ofthe pump device 106 to achieve the specified output setpoint.

Referring still to FIG. 1, the pump device 106 may take on various formsof pumps which have variable speed control. In some example embodiments,the pump device 106 includes at least a sealed casing which houses thepump device 106, which at least defines an input element for receiving acirculating medium and an output element for outputting the circulatingmedium. The pump device 106 includes one or more operable elements,including a variable motor which can be variably controlled from thecontrol device 108 to rotate at variable speeds. The pump device 106also includes an impeller which is operably coupled to the motor andspins based on the speed of the motor, to circulate the circulatingmedium. The pump device 106 may further include additional suitableoperable elements or features, depending on the type of pump device 106.Device properties of the pump device 106, including the motor speed andpower, may be self-detected by the control device 108.

Reference is now made to FIG. 2, which illustrates a graph 200 showingan example suitable range of operation 202 for a variable speed device,in this example the control pump 102. The range of operation 202 isillustrated as a polygon-shaped region or area on the graph 200, whereinthe region is bounded by a border represents a suitable range ofoperation. For example, a design point may be, e.g., a maximum expectedsystem load as in point A (210) as required by a system such as abuilding 104 at the output properties 114 (FIG. 1).

The design point, Point A (210), can be estimated by the system designerbased on the flow that will be required by a system for effectiveoperation and the head/pressure loss required to pump the design flowthrough the system piping and fittings. Note that, as pump headestimates may be over-estimated, most systems will never reach thedesign pressure and will exceed the design flow and power. Othersystems, where designers have under-estimated the required head, willoperate at a higher pressure than the design point. For such acircumstance, one feature of properly selecting one or more intelligentvariable speed pumps is that it can be properly adjusted to deliverymore flow and head in the system than the designer specified.

The design point can also be estimated for operation with multiplecontrolled pumps 102, with the resulting flow requirements allocatedbetween the controlled pumps 102. For example, for controlled pumps ofequivalent type or performance, the total estimated required outputproperties 114 (e.g. the maximum flow to maintain a required pressuredesign point at that location of the load) of a system or building 104may be divided equally between each controlled pump 102 to determine theindividual design points, and to account for losses or any non-linearcombined flow output. In other example embodiments, the total outputproperties (e.g. at least flow) may be divided unequally, depending onthe particular flow capacities of each control pump 102, and to accountfor losses or any non-linear combined flow output. The individual designsetpoint, as in point A (210), is thus determined for each individualcontrol pump 102.

The graph 200 includes axes which include parameters which arecorrelated. For example, head squared is approximately proportional toflow, and flow is approximately proportional to speed. In the exampleshown, the abscissa or x-axis 204 illustrates flow in U.S. gallons perminute (GPM) and the ordinate or y-axis 206 illustrates head (H) inpounds per square inch (psi) (alternatively in feet). The range ofoperation 202 is a superimposed representation of the control pump 102with respect to those parameters, onto the graph 200.

The relationship between parameters may be approximated by particularaffinity laws, which may be affected by volume, pressure, and BrakeHorsepower (BHP). For example, for variations in impeller diameter, atconstant speed: D1/D2=Q1/Q2; H1/H2=D1²/D2²; BHP1/BHP2=D1³/D2³. Forexample, for variations in speed, with constant impeller diameter:S1/S2=Q1/Q2; H1/H2=S1²/S2²; BHP1/BHP2=S1³/S2³. Wherein: D=ImpellerDiameter (Ins/mm); H=Pump Head (Ft/m); Q=Pump Capacity (gpm/lps);S=Speed (rpm/rps); BHP=Brake Horsepower (Shaft Power−hp/kW).

Specifically, for the graph 200 at least some of the parameters there ismore than one operation point or path of system variables of theoperable system that can provide a given output setpoint. As isunderstood in the art, at least one system variable at an operationpoint or path restricts operation of another system variable at theoperation point or path.

Also illustrated is a best efficiency point (BEP) curve 220 of thecontrol pump 102. The partial efficiency curves are also illustrated,for example the 77% efficiency curve 238. In some example embodiments,an upper boundary of the range of operation 202 may also be furtherdefined by a motor power curve 236 (e.g. maximum horsepower). Inalternate embodiments, the boundary of the range of operation 202 mayalso be dependent on a pump speed curve 234 (shown in Hz) rather than astrict maximum motor power curve 236.

As shown in FIG. 2, one or more control curves 208 (one shown) may bedefined and programmed for an intelligent variable speed device, such asthe control pump 102. Depending on changes to the detected parameters(e.g. internal or inferred detection of changes in flow/load), theoperation of the pump device 106 may be maintained to operate on thecontrol curve 208 based on instructions from the control device 108(e.g. at a higher or lower flow point). This mode of control may also bereferred to as quadratic pressure control (QPC), as the control curve208 is a quadratic curve between two operating points (e.g., point A(210): maximum head, and point C (214): minimum head). Reference to“intelligent” devices herein includes the control pump 102 being able toself-adjust operation of the pump device 106 along the control curve208, depending on the particular required or detected load.

Other example control curves other than quadratic curves includeconstant pressure control and proportional pressure control (sometimesreferred to as straight-line control). Selection may also be made toanother specified control curve (not shown), which may be eitherpre-determined or calculated in real-time, depending on the particularapplication.

Reference is now made to FIG. 3, which shows a diagram 300 illustratinginternal sensing control (sometimes referred to as “sensorless” control)of the control pump 102 within the range of operation 202, in accordancewith example embodiments. For example, an external or proximate sensorwould not be required in such example embodiments. An internal detector304 or sensor may be used to self-detect device properties such as anamount of power and speed (P, S) of an associated motor of the pumpdevice 106. A program map 302 stored in a memory of the control device108 is used by the control device 108 to map or correlate the detectedpower and speed (P, S), to resultant output properties, such as head andflow (H, F) of the device 102, for a particular system or building 104.During operation, the control device 108 monitors the power and speed ofthe pump device 106 using the internal detector 304 and establishes theassociated head-flow condition relative to the system requirements. Theassociated head-flow (H, F) condition of the device 102 can be used tocalculate the individual contribution of the device 102 to the totaloutput properties 114 (FIG. 1) at the load. The program map 302 can beused to map the power and speed to control operation of the pump device106 onto the control curve 208, wherein a point on the control curve isused as the desired device setpoint. For example, referring to FIG. 1,as control valves 112 a, 112 b, 112 c, 112 d open or close to regulateflow to the cooling coils (e.g. load 110 a, 110 b, 110 c, 110 d), thecontrol device 108 automatically adjusts the pump speed to match therequired system pressure requirement at the current flow.

Note that the internal detector 304 for self-detecting device propertiescontrasts with some conventional existing systems which may use a localpressure sensor and flow meter which merely directly measures thepressure and flow across the control pump 102. Such variables (localpressure sensor and flow meter) may not be considered device properties,in example embodiments.

Another example embodiment of a variable speed sensorless device is acompressor which estimates refrigerant flow and lift from the electricalvariables provided by the electronic variable speed drive. In an exampleembodiment, a “sensorless” control system may be used for one or morecooling devices in a controlled system, for example as part of a“chiller plant” or other cooling system. For example, the variable speeddevice may be a cooling device including a controllable variable speedcompressor. In some example embodiments, the self-detecting deviceproperties of the cooling device may include, for example, power and/orspeed of the compressor. The resultant output properties may include,for example, variables such as temperature, humidity, flow, lift and/orpressure.

Another example embodiment of a variable speed sensorless device is afan which estimates air flow and the pressure it produces from theelectrical variables provided by the electronic variable speed drive.

Another example embodiment of a sensorless device is a belt conveyorwhich estimates its speed and the mass it carries from the electricalvariables provided by the electronic variable speed drive.

FIG. 4 illustrates an example load profile 400 for a system such as abuilding 104, for example, for a projected or measured “design day”. Theload profile 400 illustrates the operating hours percentage versus theheating/cooling load percentage. For example, as shown, many examplesystems may require operation at only 0% to 60% load capacity 90% of thetime or more. In some examples, a control pump 102 may be selected forbest efficiency operation at partial load, for example on or about 50%of peak load. Note that, ASHRAE 90.1 standard for energy savingsrequires control of devices that will result in pump motor demand of nomore than 30% of design wattage at 50% of design water flow (e.g. 70%energy savings at 50% of peak load). It is understand that the “designday” may not be limited to 24 hours, but can be determined for shorteror long system periods, such as one month, one year, or multiple years.

Referring again to FIG. 2, various points on the control curve 208 maybe selected or identified or calculated based on the load profile 400(FIG. 4), shown as point A (210), point B (212), and point C (214). Forexample, the points of the control curve 208 may be optimized forpartial load rather than 100% load. For example, referring to point B(212), at 50% flow the efficiency conforms to ASHRAE 90.1 (greater than70% energy savings). Point B (212) can be referred to as an optimalsetpoint on the control curve 208, which has maximized efficiency on thecontrol curve 208 for 50% load or the most frequent partial load. PointA (210) represents a design point which can be used for selectionpurposes for a particular system, and may represent a maximum expectedload requirement of a given system. Note that, in some exampleembodiments, there may be actually increased efficiency at part load forpoint B versus point A. Point C (214) represents a minimum flow and head(Hmin), based on 40% of the full design head, as a default, for example.Other examples may use a different value, depending on the systemrequirements. The control curve 208 may also include an illustratedthicker portion 216 which represents a typical expected load range (e.g.on or about 90%-95% of a projected load range for a projected designday). Accordingly, the range of operation 202 may be optimized forpartial load operation. In some example embodiments, the control curve208 may be re-calculated or redefined based on changes to the loadprofile 400 (FIG. 4) of the system, either automatically or manually.The curve thicker portion 216 may also change with the control curve 208based on changes to the load profile 400 (FIG. 4).

FIG. 5 illustrates an example detailed block diagram of the firstcontrol device 108 a, for controlling the first control pump 102 a (FIG.1), in accordance with an example embodiment. The first control device108 a may include one or more controllers 506 a such as a processor ormicroprocessor, which controls the overall operation of the control pump102 a. The control device 108 a may communicate with other externalcontrollers 116 or other control devices (one shown, referred to assecond control device 108 b) to co-ordinate the controlled aggregateoutput properties 114 of the control pumps 102 (FIG. 1). The controller506 a interacts with other device components such as memory 508 a,system software 512 a stored in the memory 508 a for executingapplications, input subsystems 522 a, output subsystems 520 a, and acommunications subsystem 516 a. A power source 518 a powers the controldevice 108 a. The second control device 108 b may have the same, more,or less, blocks or modules as the first control device 108 a, asappropriate. The second control device 108 b is associated with a seconddevice such as second control pump 102 b (FIG. 1).

The communications subsystem 516 a is configured to communicate with,either directly or indirectly, the other controller 116 and/or thesecond control device 108 b. The communications subsystem 516 a mayfurther be configured for wireless communication. The communicationssubsystem 516 a may be configured to communicate over a network such asa Local Area Network (LAN), wireless (Wi-Fi) network, and/or theInternet. These communications can be used to co-ordinate the operationof the control pumps 102 (FIG. 1).

The input subsystems 522 a can receive input variables. Input variablescan include, for example, the detector 304 (FIG. 3) for detecting deviceproperties such as power and speed (P, S) of the motor. Other exampleinputs may also be used. The output subsystems 520 a can control outputvariables, for example one or more operable elements of the control pump102 a. For example, the output subsystems 520 a may be configured tocontrol at least the speed of the motor of the control pump 102 a inorder to achieve a resultant desired output setpoint for head and flow(H, F), for example to operate the control pump 102 onto the controlcurve 208 (FIG. 2). Other example outputs variables, operable elements,and device properties may also be controlled.

In some example embodiments, the control device 108 a may store data inthe memory 508 a, such as correlation data 510 a. The correlation data510 a may include correlation information, for example, to correlate orinfer between the input variables and the resultant output properties.The correlation data 510 a may include, for example, the program map 302(FIG. 3) which can map the power and speed to the resultant flow andhead at the pump 102, resulting in the desired pressure setpoint at theload output. In other example embodiments, the correlation data 510 amay be in the form of a table, model, equation, calculation, inferencealgorithm, or other suitable forms.

The memory 508 a may also store other data, such as the load profile 400(FIG. 4) for the measured “design day” or average annual load. Thememory 508 a may also store other information pertinent to the system orbuilding 104 (FIG. 1).

In some example embodiments, the correlation data 510 a stores thecorrelation information for some or all of the other devices 102, suchas the second control pump 102 b (FIG. 1).

Referring still to FIG. 5, the control device 108 a includes one or moreprogram applications. In some example embodiments, the control device108 a includes a correlation application 514 a or inference application,which receives the input variables (e.g. power and speed) and determinesor infers, based from the correlation data 510 a, the resultant outputproperties (e.g. flow and head) at the pump 102 a. In some exampleembodiments, the control device 108 a includes a co-ordination module515 a, which can be configured to receive the determined individualoutput properties from the second control device 108 b, and configuredto logically co-ordinate each of the control devices 108 a, 108 b, andprovide commands or instructions to control each of the outputsubsystems 520 a, 520 b and resultant output properties in aco-ordinated manner, to achieve a specified output setpoint of theoutput properties 114.

In some example embodiments, some or all of the correlation application514 a and/or the co-ordination module 515 a may alternatively be part ofthe external controller 116.

In some example embodiments, in an example mode of operation, thecontrol device 108 a is configured to receive the input variables fromits input subsystem 522 a, and send such information as detection data(e.g. uncorrelated measured data) over the communications subsystem 516a to the other controller 116 or to the second control device 108 b, foroff-device processing which then correlates the detection data to thecorresponding output properties. The off-device processing may alsodetermine the aggregate output properties of all of the control devices108 a, 108 b, for example to output properties 114 of a common load. Thecontrol device 108 a may then receive instructions or commands throughthe communications subsystem 516 a on how to control the outputsubsystems 520 a, for example to control the local device properties oroperable elements.

In some example embodiments, in another example mode of operation, thecontrol device 108 a is configured to receive input variables of thesecond control device 108 b, either from the second control device 108 bor the other controller 116, as detection data (e.g. uncorrelatedmeasured data) through the communications system 516 a. The controldevice 108 a may also self-detect its own input variables from the inputsubsystem 522 a. The correlation application 514 a may then be used tocorrelate the detection data of all of the control devices 108 a, 108 bto their corresponding output properties. In some example embodiments,the co-ordination module 515 a may determine the aggregate outputproperties for all of the control devices 108 a, 108 b, for example tothe output properties 114 of a common load. The control device 108 a maythen send instructions or commands through the communications subsystem516 a to the other controller 116 or the second control device 108 b, onhow the second control device 108 b is to control its output subsystems,for example to control its particular local device properties. Thecontrol device 108 a may also control its own output subsystems 520 a,for example to control its own device properties to the first controlpump 102 a (FIG. 1).

In some other example embodiments, the control device 108 a first mapsthe detection data to the output properties and sends the data ascorrelated data (e.g. inferred data). Similarly, the control device 108a can be configured to receive data as correlated data (e.g. inferreddata), which has been mapped to the output properties by the secondcontrol device 108 b, rather than merely receiving the detection data.The correlated data may then be co-ordinated to control each of thecontrol devices 108 a, 108 b.

Referring again to FIG. 1, the speed of each of the control pumps 102can be controlled to achieve or maintain the inferred remote pressureconstant by achieving or maintaining H=H1+(HD−H1)*(Q/QD){circumflex over( )}2 (hereinafter Equation 1), wherein H is the inferred localpressure, H1 is the remote pressure setpoint, HD is the local pressureat design conditions, Q is the inferred total flow and QD is the totalflow at design conditions. In example embodiments, the number of pumpsrunning (N) is increased when H<HD*(Q/QD){circumflex over( )}2*(N+0.5+k) (hereinafter Equation 2), and decreased ifH>HD*(Q/QD){circumflex over ( )}2*(N−0.5−k2) (hereinafter Equation 3),where k and k2 constants to ensure a deadband around the sequencingthreshold.

Reference is now made to FIG. 8, which illustrates a flow diagram of anexample method 800 for co-ordinating control of two or more controldevices, in accordance with an example embodiment. The devices eachinclude a communication subsystem and are configured to self-detect oneor more device properties, the device properties resulting in outputhaving one or more output properties. At event 802, the method 800includes detecting inputs including the one or more device properties ofeach device. At event 804, the method 800 includes correlating, for eachdevice, the detected one or more device properties to the one or moreoutput properties, at each respective device. The respective one or moreoutput properties can then be calculated to determine their individualcontributions to a system load point. At event 806, the method 800includes determining the aggregate output properties to the load fromthe individual one or more output properties. At event 808, the method800 includes comparing the determined aggregate output properties 114with a setpoint, such as a pressure setpoint at the load. For example,it may be determined that one or more of the determined aggregate outputproperties are greater than, less than, or properly maintained at thesetpoint. For example, this control may be performed using Equation 1,as detailed above. At event 810, the method includes co-ordinatingcontrol of each of the devices to operate the respective one or moredevice properties to co-ordinate the respective one or more outputproperties to achieve the setpoint. This may include increasing,decreasing, or maintaining the respective one or more device propertiesin response, for example to a point on the control curve 208 (FIG. 2).The method 800 may be repeated, for example, as indicated by thefeedback loop 812. The method 800 can be automated in that manualcontrol would not be required.

In another example embodiment, the method 800 may include a decision toturn on or turn off one or more of the control pumps 102, based onpredetermined criteria. For example, the decision may be made usingEquation 2 and Equation 3, as detailed above.

While the method 800 illustrated in FIG. 8 is represented as a feedbackloop 812, in some other example embodiments each event may representstate-based operations or modules, rather than a chronological flow.

For example, referring to FIG. 1, the various events of the method 800of FIG. 8 may be performed by the first control device 108 a, the secondcontrol device 108 b, and/or the external controller 116, either aloneor in combination.

Reference is now made to FIG. 6, which illustrates an example embodimentof a control system 600 for co-ordinating two or more sensorless controldevices (two shown), illustrated as first control device 108 a andsecond control device 108 b. Similar reference numbers are used forconvenience of reference. As shown, each control device 108 a, 108 b mayeach respectively include the controller 506 a, 506 b, the inputsubsystem 522 a, 522 b, and the output subsystem 520 a, 520 b forexample to control at least one or more operable device members (notshown).

A co-ordination module 602 is shown, which may either be part of atleast one of the control devices 108 a, 108 b, or a separate externaldevice such as the controller 116 (FIG. 1). Similarly, the inferenceapplication 514 a, 514 b may either be part of at least one of thecontrol devices 108 a, 108 b, or part of a separate device such as thecontroller 116 (FIG. 1).

In operation, the co-ordination module 602 co-ordinates the controldevices 108 a, 108 b to produce a co-ordinated output(s). In the exampleembodiment shown, the control devices 108 a, 108 b work in parallel tosatisfy a certain demand or shared load 114, and which infer the valueof one or more of each device output(s) properties by indirectlyinferring them from other measured input variables and/or deviceproperties. This co-ordination is achieved by using the inferenceapplication 514 a, 514 b which receives the measured inputs, tocalculate or infer the corresponding individual output properties ateach device 102 (e.g. head and flow at each device). From thoseindividual output properties, the individual contribution from eachdevice 102 to the load (individually to output properties 114) can becalculated based on the system/building setup. From those individualcontributions, the co-ordination module 602 estimates one or moreproperties of the aggregate or combined output properties 114 at thesystem load of all the control devices 108 a, 108 b. The co-ordinationmodule 602 compares with a setpoint of the combined output properties(typically a pressure variable), and then determines how the operableelements of each control device 108 a, 108 b should be controlled and atwhat intensity.

It would be appreciated that the aggregate or combined output properties114 may be calculated as a linear combination or a non-linearcombination of the individual output properties, depending on theparticular property being calculated, and to account for losses in thesystem, as appropriate.

In some example embodiments, when the co-ordination module 602 is partof the first control device 108 a, this may be considered a master-slaveconfiguration, wherein the first control device 108 a is the masterdevice and the second control device 108 b is the slave device. Inanother example embodiment, the co-ordination module 602 is embedded inmore of the control devices 108 a, 108 b than actually required, forfail safe redundancy.

Referring still to FIG. 6, some particular example controlleddistributions to the output subsystems 520 a, 520 b will now bedescribed in greater detail. In one example embodiment, for example whenthe output subsystems 520 a, 520 b are associated with controllingdevice properties of equivalent type or performance, the deviceproperties of each control pump 102 may be controlled to have equaldevice properties to distribute the flow load requirements. In otherexample embodiments, there may be unequal distribution, for example thefirst control pump 102 a may have a higher flow capacity than the secondcontrol pump 102 b (FIG. 1). In another example embodiment, each controlpump 102 may be controlled so as to best optimize the efficiency of therespective control pumps 102 at partial load, for example to maintaintheir respective control curves 208 (FIG. 2) or to best approach Point B(212) on the respective control curve 208.

Referring still to FIG. 6, in an optimal system running condition, eachof the control devices 108 a, 108 b are controlled by the co-ordinationmodule 602 to operate on their respective control curves 208 (FIG. 2) tomaintain the pressure setpoint at the output properties 114. This alsoallows each control pump 102 to be optimized for partial load operation.For example, as an initial allocation, each of the control pumps 102 maybe given a percentage flow allocation (e.g. can be 50% split betweeneach control device 108 a, 108 b in this example), to determine orcalculate the required initial setpoint (e.g. Point A (210), FIG. 2).The percentage responsibility of required flow for each control pump 102can then be determined by dividing the percentage flow allocation fromthe inferred total output properties 114. Each of the control pumps 102can then be controlled along their control curves 208 to increase ordecrease operation of the motor or other operable element, to achievethe percentage responsibility per required flow.

However, if one of the control pumps (e.g. first control pump 102 a) isdetermined to be underperforming or off of its control curve 208, theco-ordination module 602 may first attempt to control the first controlpump 102 a to operate onto its control curve 208. However, if this isnot possible (e.g. damaged, underperforming, would result in outside ofoperation range 202, otherwise too far off control curve 208, etc.), theremaining control pumps (e.g. 102 b) may be controlled to increase theirdevice properties on their respective control curves 208 in order toachieve the pressure setpoint at the required flow at the outputproperties 114, to compensate for at least some of the deficiencies ofthe first control pump 102 a. Similarly, one of the control pumps 102may be intentionally disabled (e.g. maintenance, inspection, saveoperating costs, night-time conservation, etc.), with the remainingcontrol pumps 102 being controlled accordingly.

In other example embodiments, the distribution between the outputsubsystems 520 a, 520 b may be dynamically adjusted over time so as totrack and suitably distribute wear as between the control pumps 102.

Reference is now made to FIG. 7, which illustrates another exampleembodiment of a control system 700 for co-ordinating two or moresensorless control devices (two shown), illustrated as first controldevice 108 a and second control device 108 b. Similar reference numbersare used for convenience of reference. This may be referred to as apeer-to-peer system, in some example embodiments. An external controller116 may not be required in such example embodiments. In the exampleshown, each of the first control device 108 a and second control device108 b may control their own output subsystems 520 a, 520 b, so as toachieve a co-ordinated combined system output 114. As shown, eachco-ordination module 515 a, 515 b is configured to each take intoaccount the inferred and/or measured values from both of the inputsubsystems 522 a, 522 b. For example, as shown, the first co-ordinationmodule 515 a may estimate one or more output properties of the combinedoutput properties 114 from the individual inferred and/or measuredvalues.

As shown, the first co-ordination module 515 a receives the inferredand/or measured values and calculates the individual output propertiesof each device 102 (e.g. head and flow). From those individual outputproperties, the individual contribution from each device 102 to the load(individually at output properties 114) can be calculated based on thesystem/building setup. The first co-ordination module 515 a can thencalculate or infer the aggregate output properties 114 at the load.

The first co-ordination module 515 a then compares the inferredaggregate output properties 114 with a setpoint of the output properties(typically a pressure variable setpoint), and then determines theindividual allocation contribution required by the first outputsubsystem 520 a (e.g. calculating 50% of the total required contributionin this example). The first output subsystem 520 a is then controlledand at a controlled intensity (e.g. increase, decrease, or maintain thespeed of the motor, or other device properties), with the resultantco-ordinated output properties being again inferred by furthermeasurements at the input subsystem 522 a, 522 b.

As shown in FIG. 7, the second co-ordination module 515 b may besimilarly configured as the first co-ordination module 515 a, toconsider both input subsystem 522 a, 522 b to control the second outputsubsystem 520 b. For example, each of the control pumps 102 may beinitially given a percentage flow allocation. Each of the control pumps102 can then be controlled along their control curves 208 to increase ordecrease operation of the motor or other operable element, based on theaggregate load output properties 114. The aggregate load outputproperties 114 may be used to calculate per control pump 102, therequire flow and corresponding motor speed (e.g. to maintain thepercentage flow, e.g. 50% for each output subsystem 520 a, 520 b in thisexample). Accordingly, both of the co-ordination modules 515 a, 515 boperate together to co-ordinate their respective output subsystems 520a, 520 b to achieve the selected output setpoint at the load outputproperties 114.

As shown in FIG. 7, note that in some example embodiments each of theco-ordination modules 515 a, 515 b are not necessarily in communicationwith each other in order to functionally operate in co-ordination. Inother example embodiments, not shown, the co-ordination modules 515 a,515 b are in communication with each other for additional co-ordinationthere between.

Although example embodiments have been primarily described with respectto the control devices being arranged in parallel, it would beappreciated that other arrangements may be implemented. For example, insome example embodiments the controlled devices can be arranged inseries, for example for a pipeline, booster, or other such application.The resultant output properties are still co-ordinated in such exampleembodiments. For example, the output setpoint and output properties forthe load may be the located at the end of the series. The control of theoutput subsystems, device properties, and operable elements are stillperformed in a co-ordinated manner in such example embodiments. In someexample embodiments the control devices can be arranged in a combinationof series and parallel.

Variations may be made in example embodiments. Some example embodimentsmay be applied to any variable speed device, and not limited to variablespeed control pumps. For example, some additional embodiments may usedifferent parameters or variables, and may use more than two parameters(e.g. three parameters on a three dimensional graph). For example, thespeed (rpm) is also illustrated on the described control curves.Further, temperature (Fahrenheit) versus temperature load (BTU/hr) maybe parameters or variables which are considered for control curves, forexample controlled by a variable speed circulating fan. Some exampleembodiments may be applied to any devices which are dependent on two ormore correlated parameters. Some example embodiments can includeselection ranges dependent on parameters or variables such as liquid,temperature, viscosity, suction pressure, site elevation and number ofpump operating.

In example embodiments, as appropriate, each illustrated block or modulemay represent software, hardware, or a combination of hardware andsoftware. Further, some of the blocks or modules may be combined inother example embodiments, and more or less blocks or modules may bepresent in other example embodiments. Furthermore, some of the blocks ormodules may be separated into a number of sub-blocks or sub-modules inother embodiments.

While some of the present embodiments are described in terms of methods,a person of ordinary skill in the art will understand that presentembodiments are also directed to various apparatus such as a serverapparatus including components for performing at least some of theaspects and features of the described methods, be it by way of hardwarecomponents, software or any combination of the two, or in any othermanner. Moreover, an article of manufacture for use with the apparatus,such as a pre-recorded storage device or other similar non-transitorycomputer readable medium including program instructions recordedthereon, or a computer data signal carrying computer readable programinstructions may direct an apparatus to facilitate the practice of thedescribed methods. It is understood that such apparatus, articles ofmanufacture, and computer data signals also come within the scope of thepresent example embodiments.

While some of the above examples have been described as occurring in aparticular order, it will be appreciated to persons skilled in the artthat some of the messages or steps or processes may be performed in adifferent order provided that the result of the changed order of anygiven step will not prevent or impair the occurrence of subsequentsteps. Furthermore, some of the messages or steps described above may beremoved or combined in other embodiments, and some of the messages orsteps described above may be separated into a number of sub-messages orsub-steps in other embodiments. Even further, some or all of the stepsof the conversations may be repeated, as necessary. Elements describedas methods or steps similarly apply to systems or subcomponents, andvice-versa.

The term “computer readable medium” as used herein includes any mediumwhich can store instructions, program steps, or the like, for use by orexecution by a computer or other computing device including, but notlimited to: magnetic media, such as a diskette, a disk drive, a magneticdrum, a magneto-optical disk, a magnetic tape, a magnetic core memory,or the like; electronic storage, such as a random access memory (RAM) ofany type including static RAM, dynamic RAM, synchronous dynamic RAM(SDRAM), a read-only memory (ROM), a programmable-read-only memory ofany type including PROM, EPROM, EEPROM, FLASH, EAROM, a so-called “solidstate disk”, other electronic storage of any type including acharge-coupled device (CCD), or magnetic bubble memory, a portableelectronic data-carrying card of any type including COMPACT FLASH,SECURE DIGITAL (SD-CARD), MEMORY STICK, and the like; and optical mediasuch as a Compact Disc (CD), Digital Versatile Disc (DVD) or BLU-RAYDisc.

Variations may be made to some example embodiments, which may includecombinations and sub-combinations of any of the above. The variousembodiments presented above are merely examples and are in no way meantto limit the scope of this disclosure. Variations of the innovationsdescribed herein will be apparent to persons of ordinary skill in theart having the benefit of the present disclosure, such variations beingwithin the intended scope of the present disclosure. In particular,features from one or more of the above-described embodiments may beselected to create alternative embodiments comprised of asub-combination of features which may not be explicitly described above.In addition, features from one or more of the above-describedembodiments may be selected and combined to create alternativeembodiments comprised of a combination of features which may not beexplicitly described above. Features suitable for such combinations andsub-combinations would be readily apparent to persons skilled in the artupon review of the present disclosure as a whole. The subject matterdescribed herein intends to cover and embrace all suitable changes intechnology.

1. A control system, comprising: two or more devices each having arespective internal sensor and each having a respective operableelement, each device having a communication subsystem and configured toself-detect one or more device properties of the operable element, thedevice properties resulting in output having two or more outputproperties; at least one memory which stores, for each device,correlation data between the one or more device properties and the twoor more output properties for that device; and one or more controllersconfigured to, using sensor data from the respective internal sensorsand without using sensor data from an external sensor that is externalto the devices: detect the one or more device properties self-detectedby each device, correlate, for each device, based on the storedcorrelation data, the detected one or more device properties to the twoor more output properties for that device, determine, for each device, avalue of the two or more output properties for that device which resultin combined output of the devices achieving an output setpoint,co-ordinate control of each device to operate their respective one ormore device properties, based on the stored correlation data, theirrespective determined value of the two or more output properties forthat device, and increase or decrease a number of the devices beingoperated at their respective one or more device properties in order toachieve the output setpoint.
 2. The control system as claimed in claim1, wherein the one or more device properties comprises two or moredevice properties that are correlated, and wherein the two or moreoutput properties are correlated with each other and with the two ormore device properties.
 3. The control system as claimed in claim 1,wherein the two or more output properties include a pressure variableand a flow variable, wherein the pressure variable is a local pressurevariable that is local to the respective device.
 4. The control systemas claimed in claim 3, wherein the output setpoint is a remote pressuresetpoint that is remote to the devices, wherein a speed variable of eachdevice is controlled to achieve the remote pressure setpoint byachieving H=H1+(HD−H1)*(Q/QD){circumflex over ( )}2, wherein H is thecorrelated local pressure variable that is local to the devices, H1 isthe remote pressure setpoint, HD is a local pressure at designconditions, Q is a total of the correlated flow variables and QD is atotal flow at design conditions.
 5. The control system as claimed inclaim 4, wherein the number of the devices being operated (N) isincreased when H<HD*(Q/QD){circumflex over ( )}2*(N+0.5+k), anddecreased if H>HD*(Q/QD){circumflex over ( )}2*(N−0.5−k2), wherein k andk2 are constants to ensure a deadband around a sequencing threshold. 6.The control system as claimed in claim 2, wherein said correlating foreach device is determined from a mapping from the two or more deviceproperties to the two or more output properties.
 7. The control systemas claimed in claim 2, wherein each of the respective device propertiesare controlled to operate on a respective control curve defined by thetwo or more output properties.
 8. The control system as claimed in claim1, wherein the operable element is a variably controllable motor,wherein the one or more device properties includes a speed variable ofthe variably controllable motor of the respective device.
 9. The controlsystem as claimed in claim 1, wherein each of the respective deviceproperties are controlled to optimize efficiency at partial operation ofthe devices.
 10. The control system as claimed in claim 1, wherein thecombined output is an aggregate output to a varying load, wherein thevarying load affects the detected one or more device properties.
 11. Thecontrol system as claimed in claim 1, wherein the devices are arrangedin at least one of a parallel configuration, a series configuration, ora combination of parallel and series configuration.
 12. The controlsystem as claimed in claim 1, wherein the output setpoint is fixed,continually or periodically calculated, or externally determined. 13.The control system as claimed in claim 1, wherein the two or more outputproperties relate to a remote location to the devices.
 14. The controlsystem as claimed in claim 1, wherein each device includes an outputsubsystem for controlling the operable element, wherein the operableelement has the device properties.
 15. The control system as claimed inclaim 1, wherein one device includes at least one of the controllersconfigured to perform said co-ordinating control.
 16. The control systemas claimed in claim 1, further comprising an external device to thedevices configured to perform said co-ordinating control.
 17. Thecontrol system as claimed in claim 1, wherein one device is configuredto perform said correlating for each device.
 18. The control system asclaimed in claim 1, wherein said co-ordinating includes said increasingor decreasing the number of the devices being operated.
 19. The controlsystem as claimed in claim 1, wherein the control system furthercomprises a chilled circulating system including a refrigerant, whereinat least one device includes a compressor having a variably controllablemotor having the one or more device properties resulting in the outputproperties including lift and flow for the refrigerant.
 20. The controlsystem as claimed in claim 1, wherein the control system furthercomprises an interface in thermal communication with a secondarycirculating system and one or more cooling or heating elements at theinterface, wherein a varying load for the combined output to achieve theoutput setpoint includes demand defined by the one or more cooling orheating elements.
 21. The control system as claimed in claim 1, whereinsaid devices are circulating devices.
 22. A method for co-ordinatingcontrol of two or more devices each having a respective internal sensorand each having a respective operable element, each device having acommunication subsystem and configured to self-detect one or more deviceproperties of the operable element, the device properties resulting inoutput having two or more output properties, wherein the one or moredevice properties, wherein at least one memory stores, for each device,correlation data between the one or more device properties and the twoor more output properties for that device, the method being performedusing sensor data from the respective internal sensors and without usingsensor data from an external sensor that is external to the devices, themethod comprising: detecting the one or more device propertiesself-detected by each device; correlating, for each device, based on thestored correlation data, the detected one or more device properties tothe two or more output properties for that device; determining, for eachdevice, a value of the two or more output properties for that devicewhich result in combined output of the devices achieving an outputsetpoint; co-ordinating control of each device to operate theirrespective one or more device properties, based on the storedcorrelation data, their respective determined value of two or moreoutput properties for that device; and increasing or decreasing a numberof the devices being operated at their respective one or more deviceproperties in order to achieve the output setpoint.
 23. The method asclaimed in claim 22, wherein the one or more device properties comprisestwo or more device properties that are correlated, and wherein the twoor more output properties are correlated with each other and with thetwo or more device properties.
 24. The method as claimed in claim 22,wherein the two or more output properties include a pressure variableand a flow variable, wherein the pressure variable is a local pressurevariable that is local to the respective device.
 25. The method asclaimed in claim 24, wherein the output setpoint is a remote pressuresetpoint that is remote to the devices, wherein a speed variable of eachdevice is controlled to achieve the remote pressure setpoint byachieving H=H1+(HD−H1)*(Q/QD){circumflex over ( )}2, wherein H is thecorrelated local pressure variable that is local to the devices, H1 isthe remote pressure setpoint, HD is a local pressure at designconditions, Q is a total of the correlated flow variables and QD is atotal flow at design conditions.
 26. The method as claimed in claim 25,wherein the number of the devices being operated (N) is increased whenH<HD*(Q/QD){circumflex over ( )}2*(N+0.5+k), and decreased ifH>HD*(Q/QD){circumflex over ( )}2*(N−0.5−k2), wherein k and k2 areconstants to ensure a deadband around a sequencing threshold.
 27. Themethod as claimed in claim 23, wherein said correlating for each deviceis determined from a mapping from the two or more device properties tothe two or more output properties.
 28. The method as claimed in claim23, wherein each of the respective device properties are controlled tooperate on a respective control curve defined by the two or more outputproperties.
 29. The method as claimed in claim 22, wherein the operableelement is a variably controllable motor, wherein the one or more deviceproperties includes a speed variable of the variably controllable motorof the respective device.
 30. The method as claimed in claim 22, whereineach of the respective device properties are controlled to optimizeefficiency at partial operation of the devices.
 31. The method asclaimed in claim 22, wherein the combined output is an aggregate outputto a varying load, wherein the varying load affects the detected one ormore device properties.
 32. The method as claimed in claim 22, whereinthe devices are arranged in at least one of a parallel configuration, aseries configuration, or a combination of parallel and seriesconfiguration.
 33. The method as claimed in claim 22, wherein the outputsetpoint is fixed, continually or periodically calculated, or externallydetermined.
 34. The method as claimed in claim 22, wherein the two ormore output properties relate to a remote location to the devices. 35.The method as claimed in claim 22, wherein each device includes anoutput subsystem for controlling the operable element, wherein theoperable element has the device properties.
 36. The method as claimed inclaim 22, wherein one device is configured to perform said co-ordinatingcontrol.
 37. The method as claimed in claim 22, wherein an externaldevice is configured to perform said co-ordinating control.
 38. Themethod as claimed in claim 22, wherein one device is configured toperform said correlating for each device.
 39. The method as claimed inclaim 22, wherein said co-ordinating includes said increasing ordecreasing the number of the devices being operated.
 40. The method asclaimed in claim 22, for a chilled circulating system including arefrigerant, wherein at least one device includes a compressor having avariably controllable motor having the one or more device propertiesresulting in the output properties including lift and flow for therefrigerant.
 41. The method as claimed in claim 22, for a temperaturecontrol system which includes an interface in thermal communication witha secondary circulating system and one or more cooling or heatingelements at the interface, wherein a varying load for the combinedoutput to achieve the output setpoint includes demand defined by the oneor more cooling or heating elements.
 42. The method as claimed in claim22, wherein said devices are circulating devices.
 43. The method asclaimed in claim 22, wherein the method is performed by one or moreprocessors.
 44. A non-transitory computer readable medium havinginstructions stored thereon executable by one or more processors forco-ordinating control of two or more circulating devices each having arespective internal sensor and each having a respective operableelement, each device having a communication subsystem and configured toself-detect one or more device properties of the operable element, thedevice properties resulting in output having two or more outputproperties, wherein the one or more device properties, wherein at leastone memory stores correlation data between the one or more deviceproperties and the two or more output properties for that device, theco-ordinating control being executed using sensor data from therespective internal sensors and without using sensor data from anexternal sensor that is external to the devices, the instructionscomprising: instructions for detecting the one or more device propertiesself-detected by each device; instructions for correlating, for eachdevice, based on the stored correlation data, the detected one or moredevice properties to the two or more output properties for that device;instructions for determining, for each device, a value of the two ormore output properties for that device which result in combined outputof the devices achieving an output setpoint; instructions forco-ordinating control of each device to operate their respective one ormore device properties to achieve, based on the stored correlation data,their respective determined value of the two or more output propertiesfor that device, and instructions for increasing or decreasing a numberof the devices being operated at their respective one or more deviceproperties in order to achieve the output setpoint.
 45. Thenon-transitory computer readable medium as claimed in claim 44, for achilled circulating system including a refrigerant, wherein at least onedevice includes a compressor having a variably controllable motor havingthe one or more device properties resulting in the output propertiesincluding lift and flow for the refrigerant.